Erratum: Thermoelectric Instability of Some Noble Metal Thermocouples at High Temperatures

A pan-European investigation of the Pt-40%Rh/Pt-20%Rh (Land–Jewell) thermocouple reference function

“…It has been observed that the thermoelectric stability of Pt-Rh alloys used in air at high temperatures is independent of wire diameter [6,7,39], and hence in principle the reference function could be determined with any diameter wire. For these measurements, a wire diameter of 0.5 mm was used as the best compromise between ease of use with the available facilities, and robustness.…”

“…The lower output of the Land-Jewell thermocouple relative to the type B thermocouple, previously considered a drawback, is mitigated these days by the prevalence of very sensitive digital voltmeters, provided its use is restricted to temperatures in excess of 400 °C. As well as the advantage of its high melting temperature, its high Rh content relative to the letter-designated thermocouples lends it greater stability than the other Pt-Rh thermocouple types above about 1200 °C [2] and, in addition, its performance is far superior to the refractory metal W-Re thermocouples [3][4][5] under a wide range of conditions [6][7][8]. This is because alloys with high Rh content are less sensitive to local changes in Rh content caused by evaporation of the oxides of Pt and Rh which are very volatile at high temperatures [9,10].…”